Jackknife boom



Feb. 23, 1965 A. H. WlLKlNSON 3,170,574

JACKKNIFE BOOM Filed April 5, 1962 2 Sheets-Sheet 1 United States Patent 3,179,574 JACKKNIFE BUOM Alvin H. Wilkinson, Tulsa, Okla, assiguor to Auto Crane Company, Tulsa, Okla, a corporation of Oklahoma Filed Apr. 5, 1962, Ser. No. 185,381 Claims. (Cl. 212-144) This invention relates to improvements in cranes and more particularly, but not by way of limitation, to a crane structure adapted for installation on a vehicle, or the like, and particularly designed and constructed for change from a stowage position to an operating position with maximum speed and minimum effort.

There are many cranes having folding or jacknife type boom structures available today for mounting on a vehicle, such as that disclosed in the T. S. Holmes Patent No. 2,682,957, issued July 6, 1954, and entitled Crane With Folding Boom. These presently available devices, however, have many disadvantages. For example, the folding boom members usually constitute a cantilever member in operation wherein bending stresses are transmitted thereto during the lifting of a load. It is well known in the machine design art that a column load is less critical on a supporting member than an equivalent cantilever load. Thus, the utilization of the cantilever boom somewhat limits the load carrying capacities of the apparatus. In addition, the hinge pin connecting the sections of the boom is usually submitted to considerable stress during utilization of the crane, and the limitations thereof greatly reduce the load handling capabilities of the boom. Furthermore, the jackknife booms in use today normally require individual and different types of drive mechanisms for folding of the boom and operation of the crane, which necessitates a multiplicity of components and also increases the time and effort required for moving the boom from the folded or stowage position to the extended or operating position.

The present invention contemplates a novel jacknife type crane structure wherein the geometric construction thereof in the operating position is such that a triangular truss is provided whereby the boom member constitutes a compression member. The stresses in the compression member are similar to those in a column under compressive load, which greatly increases the load handling conditions which may be efficiently achieved with the crane. The sections of the boom are connected in such a manner that the hinge pin functions only as a positioning and retaining member and carries no compression load whatsoever during operation of the crane. The compressive load applied to the uppermost section of the boom is transmitted directly to the lowermost section, thereby utilizing the full cross section of the boom tubing joint. The truss-type construction or configuration places the boom structure in compression as a column, and not in bending as in the case of a cantilevered boom.

The hoisting drum of the novel crane is motor driven through a gear train, and the boom positioning hoist is driven by means of an identical drive mechanism, thus providing for standardization of components. In addition, the boom hoist not only functions for positioning the boom under load, but also serves to manipulate the boom to the folded or jackknifed position for stowage, or over-the-road position. As a result, the crane can be changed from the stowage position to the operation position with great speed and with a minimum of effort on the part of the operator, and in the operating position, maximum utilization of the boom structure is provided with a minimum of parts. This permits a lighter and less expensive structure with optimum utility and speed of operation.

' It is an important object of this invention to provide an improved crane wherein the boom member is in compres- "ice sion during operation of the crane for greatly increasin the load handling capacities of the apparatus.

t is another object of this invention to provide an in proved crane of the jackknife boom type wherein th hinge pin connecting the sections of the boom is not sul jected to compressive loads during the operation of th crane.

Another object of this invention is to provide a now jackknife type crane particularly designed and constructe to facilitate changing thereof from the folded position t the operating position with maximum speed and minimui effort.

A further object of this invention is to provide a now crane of the jackknife boom type wherein the maximui utilization of the boom structure is provided with a min mum of components for a light weight constructio adapted to portability.

A still further object of this invention is to provide novel crane which is simple and eificient in operation an economical and durable in construction.

Other and further objects and advantageous features the present invention will hereinafter more fully appear i connection with a detailed description of the drawings i which:

FIGURE 1 is a side elevational view of a crane strut ture embodying the invention, and depicting a plurality positions therefor in dotted lines.

FIGURE 2 is a broken side elevational view of ti hinged joint between the boom sections depicting tf boom in a folded position.

FIGURE 3 is a perspective view of the hinged joint b1 tween the boom sections and depicting the boom in an e; tended or operating position.

FIGURE 4 is a View taken on line 4-4 of FIGURE 1 FIGURE 5 is a front elevational view of the upper en portion of the boom.

Referring to the drawings in detail, reference charactt 10 generally indicates a crane comprising a substantial] vertical pedestal member 12 rotatably journalled on suitable base 14 by means of a turn table 16 in any we known manner (not shown). The base 14 may be rigid] secured to the bed of a vehicle (not shown), if desire but it is to be understood that the crane It is not in at manner limited to installation of a vehicle. A section: boom member 18 is pivotally secured to the pedestal 1 at 20 in any suitable manner, such as by a pivot pin jou nailed between a pair of spaced flanges 22, only one which is indicated in FIGURE 1, and which is depicte broken for purposes of illustration.

The boom 18 comprises an upper section 24 hingedl secured to a lower section 26 for a purpose as will be herl inafter set forth. The lower section 26 is preferably 001 structed from square tubing, but is not limited therett and is provided with a plurality of spaced, outwardly e: tending apertured flanges 28 at the upper end thereof f( receiving a hinge pin 30 therethrough. A pair of $111 stantially identical bracket or guide plate members 3 and 34 (FIGURES 3 and 4) are rigidly secured to tl opposed sides of the section 26 in the proximity of ti upper end thereof but spaced slightly downwardly then from, and extend outwardly in an opposite direction fro] the flanges 28. A suitable roller 36 is journalled betwee the bracket or guide plates 32 and 34, and a pair of stc members 38 (only one of which is shown) are rigid: secured to opposite sides of the section 26 in the proximit of the plates 32 and 34 for a purpose as will be hereinaftt set forth. A pair of oppositely disposed outwardly e: tending latching pin members 48 (only one of which shown in FIGURE 1) are provided on the lower sectic 26 and spaced below the upper end thereof for coopera ing with a latching mechanism generally indicated at E for securely retaining the section 26 in a substantially u v 3 t or vertical position when it is desired to fold or jacke the boom 18. The latch may be of any suitable and is preferably suitably secured to the pedestal 1nd connected to a lanyard 52 whereby the latch 50 be readily manipulated by remote control, as will be :inafter set forth in detail. he upper section 24 of the boom 18 is also preferably itructed from square tubing, but not limited thereto, is provided with a pair of spaced plate members 54 56 rigidly secured to opposite sides of the section 24 extending slightly below the lower end thereof, as rly shown in FIGURES 2 and 3. The plates 54, 56 substantially identical and may be of any suitable conration whereby the opposite extremities thereof exbeyond the opposed faces or sides of the section'24. left hand portions 58 thereof, as viewed in the draware spaced slightly outwardly from the hinge flanges and are apertured for receiving the hinge pin 30 ethrough whereby the upper section 24 is hingedly red to the lower section 26. The right hand end 60 62 of the plates 54 and-56, respectively, are substany co-planar with the guide plates 32 and 34 and abut eagainst simultaneously with the abutment of the cent ends of the sections 24 and 26 in the operating xtended position of the boom 18. A roller 64 similar he roller 36 is suitably journalled between the end ions 60 and 62 for a purpose as will be hereinafter forth. In addition, a plate member 66 is rigidly sed to the section 24 between the end portions 60 and and extends below the lower end of the section 24 1bstantia1 alignment with the lower edge 68 and 70 of plates 54 and 56 for strengthening of the joint between sections 24 and 26 in the operating position of the m 18.

will be apparent that the upper section 24 may be tted about the hinge pin 30 in order to provide a knifed or folded position for the boom 18, and as vn in detail in FIGURE 2. The stopmembers 38 .he lower section 26 are so arranged with respect to emembers 54 and 56 on the upper section 24 whereby lower edges 68 and 70 of the plates contact the rear 72 of the stop members for limiting the counterclock- :.rotation of the section 24, as viewed in the drawings. precludes a complete revolution of the upper section md provides a substantially horizontal disposition for upper section 24 in the fully folded or jackknifed tion of the boom 18, as particularly shown in FIG- E 1, and as will be hereinafter set forth in detail. he upper end 74 of the upper section 24 is provided I a plurality of side plate members 76, 77, 78 and 79. plates 76' and 77 are spaced at one side of the section and the plates 78 and 79 are spaced at the opposite of the section 24, as clearly shown in FIGURE 5. plates are preferably rigidly secured to the end por- 74 by means of a pin or shaft 80 extending thereugh and welded thereto. The complementary pairs alates 76 and 77 are spaced to provide guide plates support .a pair of sheaves 81 and 82 journalled on a 83, and the complementary pairs of plates 78 and 79 spaced to provide guide plates and to support a second of sheaves 84 and 85, also journalled on the pin 83. oom cable 88 and a second cable or hoist line 90 are aded or strung around the sheaves 81, 82, 84 and uch a manner that the resultant loads imposed on the m 18 are concentrically applied about the longitudinal :er line of the boom. he boom cable 88 extends from a suitable boom hoist vinch 92 and around the sheave 85 to a suitable cross we or block member -94, around the block 94 and r-to the sheave 81 to a dead end anchor (not shown) I as normally provided in the proximity of the drum loi-st 92. The hoist cable extends from a hoist or :h 96 and around the sheave 84 to a suitable hook :k 98, around the hook block 98 and over the sheave o a dead end anchor (not shown) preferably provided 4 in the proximity of the drum or winch 96. It will thus be apparent that stringup is such that both the boom cable 88 and the hoist cable 90 are disposed over sheaves on each side of the boom 18 for distributing the load evenly about the center line of the boom. An eye member 100 is secured to the outer periphery of the upper boom section 24, and spaced slightly from the lower end thereof H whereby the hook block 98 may be hooked or secured therein when it is desired to jackknife the boom 18 for any reason. Of course, the boom hoist 92 and the hoist or drum 96 are both motor driven through a gear train (not shown), and are provided Withsubstantially identical drive mechanisms to provide for standardization of components. The boom hoist 92 not only functions for manipulating the boom to the folded or jackknifed position, but also functions for positioning the boom under load during the operation position thereof.

As hereinbefore set forth, the latch 50 may be of any suitable type which may be released by remote control for facilitating operation thereof. As depicted herein, the latch 50 preferably comprises a pair of spaced link arms 102 (only one of which is shown in FIGURE 1) I which transversely span the lower section 26, and each 7 counterclockwise, or reverse direction, and the rotation.

direction, as viewed in FIGURE 1. notches 104 will be lifted from the engagement with the having a notch or recess 104 therein for engaging the oppositely disposed pins 48. The link arms 102 are pivotally secured to the pedestal 12 at 106 whereby they may be pivoted in a direction for release from the engagement between the notches 104 and pins 48. In order to pivot pins 48 for releasing the lower section 26 of the boom 18. It is to be noted that release of the pressure on the lanyard 52 Will permit the latch arms 102 to rotate in a thereof is limited whereby a clockwise pivoting of the lower section 26 will bring the pins 48 into contact with the latch arms 102 and automatically engage the pins 48 in the notches 104 for securing the section 26 in a substantially vertical position, and for a purpose as will be hereinafter set forth.

Operation When it is desired to use the hoist or crane 10 for manipulation of a load, such as when loading or unloads ing materials from the bed of'a truck, or the like, the boom 18 is disposed in the extended or operating position A as shown in solid lines in FIGURE 1. The upper section 24 is so positioned with respect to the lower section 26 that the adjacent ends thereof are in abutting relation. In this manner, a triangular shaped truss is formed whereby the loads carried by the boom are compressive, and the abutment of the two sections 24 and 26 transmits the compressive force direction to the lower section whereby there is no stress or load on the hinge pin 30, and the entire cross sectional area of the lower section 26 may be utilized. The lanyard 52 may be utilized. for releasing the latching engagement between the latch 50 and pins 48, and the entire boom 18 may be lowered or raised by means of the boom hoist 92 and boom hoist cable 88 in the usual manner to the desired working or operating position B .as shown in dotted linesin FIGURE 1. The block hook 98 may be utilized as is well known for handling of the load to be moved or manipulated.

When the boom 18 is to be folded or jackknifed into a stowage position C, shown in dotted lines in FIGURE 1, the boom hoist 92 and cable 88 are utilized in the usual manner for elevating or pivoting the boom 18 to the substantially vertical posit-ion A. The clockwise pivoting of the boom 18 about the pivot 20 automatically engages the pins 48 in the notches 104 for securely" latching the lower section 26 in the substantially vertical position, and precluding rotation thereof in an opposite or counterclockwise direction. The boom hoist 92 is then operated for lowering of the boom 18 whereby the upper section 24 will pivot about the hinge pin 30 in a counterclockwise direct-ion, as viewed in the drawings, to the substantially horizontal position C. The counterclockwise rotation of the upper section 24 is limited by the contact of the plate members 54 and 56 with the stop members 38. The rollers 36 and 64 and guide plates 32 and 34 assure that the hoist line 590 remains on the top or upper side of the boom section 24 in the lowered position thereof, and precludes chafing of the line 90 against any sharp edges, or the like. The hook block 98 may then be secured in the eye member 100 to preclude free swinging of the line when the boom 18 is in the lowered or stowage position. The boom 18 is thus folded or jackknifed into the stowage position until it is desired to use the crane 1i! once again.

In order to place the boom 18 in an operation position from the stowage position, the sequence of operation set forth hereinbefore is reversed. The boom hoist 92 is operated for raising the boom whereby the upper section 24 will pivot in a clockwise direction around the hinge pin 36. The section 24 will continue to pivot about the pin 30 until the lower end thereof is brought into contact or abutment with the upper end of the lower section 26. The latch 50 may then be released by actuation of the lanyard 52 for releasing the lower section 26 from the latched position, and the boom 18, in the extended or working position, may be manipulated for handling of the load. Of course, the hook block 98 may be manually released from the engagement with the eye 100 prior to the raising of the section 24, or at any desired time during the raising operation.

It will be apparent that the raising or lowering of the boom 18 to provide alternate working and stowage positions therefor may be accomplished in a minimum of time and with a minimum of effort. The stowage of the boom with the upper section 24 thereof in the substantially horizontal position precludes interference of the boom with the cargo loaded or stowed on the vehicle wherein the crane is mounted. In addition, it is to be noted that the upper section 24 may be lowered either toward the rear of the vehicle, or forwardly toward the cab section since the horizontal section 24 may be disposed either over the cab, or above the bed of the vehicle. Of course, the pedestal 12 is rotatably mounted on the base 14 for complete rotation through an angle of 360 degrees, thus providing no limit to the direction in which the crane 10 may beutilized for handling the load.

From the foregoing, it will be apparent that the present invention provides .a novel crane wherein the boom thereof may be folded or jackknifed readily and simply with a minimum of effort, and alternately moved to a working or operation position with equal ease and speed. The boom hoist not only functions for raising and lowering the boom in the working position thereof, but also serves to lower the upper section of the boom to provide the jackknifed position therefor. The triangular truss configuration of the crane is such that the boom member constitutes a compression member wherein increased loads may be efficiently'handled thereby. The compressive load in the boom is transmitted directly to the lower section thereof wherebythe entire cross section of the boom tubing at the joint may be utilized. In addition, the hinge pin functions only as a positioning and retaining member, and does not carry the compressive load of the boom column. .The novel crane device is simple and efficient in operation and economical and durable in construction.

Whereas, the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications,

apart from those shown or suggested herein, may be ma within the spirit and scope of this invention.

What is claimed is: 1. A crane comprising pedestal means, boom means pivotally secured to the pedestal meal hinge means provided on said boom means to provi alternate positions for stowage and working, means for raising and lowering the boom in the wor ing position thereof, latch means provided on the pedestal for cooperati:

with the boom and hinge to provide for folding the boom to the stowage position and maintaini: the boom in said stowage position independent from any auxiliary equipment, and said last mentioned means also cooperating wi the hinge means for raising and lowering the boc from the work-ing position to the stowage positir thereof, and means carried by the boom for limiting the H10 ment thereof during lowering to the stowage po tion. 2. A crane comprising pedestal means, boom means pjvotally secured to the pedestal mea whereby a triangular truss is formed, hinge means provided on said boom means to provi alternate positions for stowage and Working, latch means cooperating between the pedestal mea and boom means to provide for folding of the boc into the stowage position independently from a: auxiliary equipment, means for raising and lowering the boom while the working position and for raising and loweri: the boom from the working position to the stowa position thereof, said last mentioned means bei disposed and arranged with respect to the boom preclude eccentric loading on the boom during c eration thereof said boom in the working position comprising a CO] pression member whereby compression load is p1 eluded from the hinge means, and stop means 02 ried by the boom for limiting the movement there during lowering to the stowage position. 3. A crane comprising pedestal means, sectional boom means pivotally secured to the pedes: means to provide a triangular truss whereby t boom is placed in compression under load duri working conditions thereof, hinge means provided for the boom means to provi for jackknifing thereof latch means provided on the pedestal means for c operation with the hinge means and one secti= of the boom means to provide for jackknifing the boom independently from any auxiliary suppt equipment, means for raising and lowering the boom in the wor ing conditions thereof, and said last mentioned means also cooperating wi the hinge means for alternately changing the boc from the working condition to the jackknifed 1; sition thereof, and stop means carried by the boc for limiting the movement thereof during changi thereof to the jackknifed position. 4. In a crane, pivotal boom means,

hinge means provided on the boom means to provi for jackknifing thereof to alternate working positio and stowage positions, latch means cooperating with the hinge means topr vide the jackknifing of the boom means, means provided on the boom means in the proxim: of the hinge means for limiting the jackknifing moi ment in one direction to provide a substantiai horizontal position of one portion of the boom means in the jackknife position,

isting means for pivoting the boom in the working position thereof and cooperating with the hinge means and latch means for jackknifing of the boom means,

d said iboo-m means comprising a plurality of sections disposed in end to end abutment in the working position thereof to preclude load on the hinge means in the working position of the boom.

A crane comprising destal means,

:tional boom means pivotally secured to the pedestal means and disposed in end to end abutment in a working position of the boom whereby a triangular truss is provided during operation of the boom for placing the boom under compressive loads,

age means provided on the boom means for providing alternate positions of working and stowage for the boom means,

ch means carried by the pedestal means and cooperating with the hinge means to provide the stowage position for the boom means independently from any auxiliary support equipment,

:ans carried by the boom for cooperating between two sections of the boom means for limiting the movement of the boom during lowering thereof into a stowage position,

d hoist means for pivoting the boom means during the Working position thereof and cooperating with the hinge means and latch means for raising and lowering of the boom to provide the alternate stowage and working positions therefor.

In a crane,

sectional pivotal boom,

lge means connecting the sections of the boom for alternate positions of extended and jackknifed,

:ch means cooperating with the hinge means to provide the jackknifed position of the boom,

d said sections of said boom disposed in abutting relationship in the extended position of the boom for precluding load on the hinge means during operation of the boom, and means provided on said boom for cooperation between two sections thereof for limiting the movement of one section during jackk-nifing of the boom for independently maintaining a substantially horizontal position for the said one section in the jackknifed position of the boom.

In a crane,

sectional pivotal boom as set forth in claim 6 wherein hoist means is provided for lowering and raising of the boomin the working position thereof and cooperating with the hinge means for lowering and raising of the boom to and from the jackknifed position thereof, and said hoist means being disposed and arranged with respect to the boom to preclude eccentric loading on the boom during operation thereof.

A crane structure comprising destal means,

:tional boom means pivotally secured to the pedestal means,

nge means securing the boom sections together to provide for jackknifing thereof to alternate working positions and stowage positions,

:ch means carried by the pedestal means for cooperating with the hinge means to provide the jackknifed position for the boom,

)p means provided on the boom means for cooperating between two sections thereof to limit the movement of one section during jackknifing of the boom to provide a substantially horizontal position for the said one section in the jackknifed position,

said boom sections disposed in abutting position in the working position of the boom to preclude any load on the hinge means during operation of the boom,

hoist line means for pivoting of the boom in the working position thereof and for cooperation with the hinge means to provide for the jackknifing of the boom,

and means for retaining the hoist line on the upper side of the boom in the jackknifed position thereof.

9. In a crane,

pivotal boom means,

hinge means provided on the boom means to provide for jackknifing thereof to alternate working and stowage positions,

latch means cooperating with the hinge means to provide said jackknifing of the boom stop means carried by the boom means for limiting the movement of the boom during jackknifing thereof whereby a portion of the boom will be maintained in a substantially horizontal position in the stowage position thereof,

boom hoisting means for pivoting of the boom means in the working position thereof and for cooperating with the hinge means for jackknifing of the boom means,

load hoisting means cooperating with the boom means for manipulation of a load during operation of the crane,

and means carried by the boom means and vcooperating with the boom hoisting means and load hoisting means for distributing the load on the boom means concentrically about the center line thereof during operation of the crane.

10. In a crane,

a sectional boom member,

hinge means connecting the sections of the boom to provide for alternate extended and jackknifed positions therefor,

said boom sections disposed in abutting relationship in the extended position thereof for precluding load on the hinge means during operation of the boom,

sto-p means provided on one section of the boom for limiting rotation of the other section of the boom' References Cited in the file of this patent UNITED STATES PATENTS 2,689,656 Przybylski Sept. 21, 1954 2,809,756 Bannister Oct. 15, 1957' 7 Troche May 12, 1959 2,388,151 Morris May 26, 1959 3, 57 Thomas Jan. 15, 1963 

6. IN A CRANE, A SECTIONAL PIVOTAL BOOM, HINGE MEANS CONNECTING THE SECTIONS OF THE BOOM FOR ALTERNATE POSITIONS OF EXTENDED AND JACKKNIFED, LATCH MEANS COOPERATING WITH THE HINGE MEANS TO PROVIDE THE JACKKNIFED POSITION OF THE BOOM, AND SAID SECTIONS OF SAID BOOM DISPOSED IN ABUTTING RELATIONSHIP IN THE EXTENDED POSITION OF THE BOOM FOR PRECLUDING LOAD ON THE HINGE MEANS DURING OPERATON OF THE BOOM, AND MEANS PROVIDED ON SAID BOOM FOR COOPERATION BETWEEN TWO SECTIONS THEREOF FOR LIMITING THE MOVEMENT OF ONE SECTION DURING JACKKNIFING OF THE BOOM FOR INDEPENDENTLY MAINTAINING A SUBSTANTIALLY HORIZONTAL POSITION FOR THE SAID ONE SECTION IN THE JACKKNIFED POSITION OF THE BOOM. 